Wireless communication systems, such as the 3rd Generation (3G) of mobile telephone standards and technology, are well known. An example of such 3G standards and technology is the Universal Mobile Telecommunications System (UMTS™), developed by the 3rd Generation Partnership Project (3GPP™) (www.3gpp.org).
The 3rd and 4th generations of wireless communications, and particular systems such as LTE, have generally been developed to support macro-cell mobile phone communications. Here the ‘phone’ may be a smart phone, or another mobile or portable communication unit that is linked wirelessly to a network through which calls are connected. Henceforth all these devices will be referred to as mobile communication units. Calls may be data, video, or voice calls, or a combination of these. Such macro cells utilise high power base stations to communicate with wireless communication units within a relatively large geographical coverage area. The coverage area may be several square kilometers, or larger if it is not in a built-up area.
Typically, mobile communication units communicate with each other and other telephone systems through a network. In a 3G system, this is the ‘Core Network’ of the 3G wireless communication system, and the communication is via a Radio Network Subsystem. A wireless communication system typically comprises a plurality of Radio Network Subsystems. Each Radio Network Subsystem comprises one or more cells, to which mobile communication units (UEs) may attach, and thereby connect to the network. A base station may serve a cell with multiple antennas, each of which serves one sector of the cell.
Overview of Prior Art Approaches
Every time a mobile communication unit makes a call via a network, several messages are sent inside the mobile network. These messages allow the call to take place. In prior art approaches, these messages have generally been discarded. The decision to discard these messages results from the massive rate of generation of these messages. The resulting volume of messages has been considered too great to store. If these messages are collected, then they tend to be collected for a short period of time. This is generally less than one day. The messages are then processed offline. The processing is typically carried out in order to look for a specific problem in a network, such as one reported by a user.
In the prior art, it is known to extract network data from a radio network controller (RNC) or similar network element. This data may be processed to provide geographic location information, for the users and their associated quality of service information. This is typically achieved either by:    (i) ‘Probing’ a suitable data flow, for example between the RNC and another network element. That network element may be the operational support system, or ‘OSS’.    (ii) Extracting data directly from the operational support system, or other suitable component connected directly to the radio network controller.
Given that the probed data or extracted data is provided by a single item of equipment, it is then possible to route the information directly to a suitably large processing unit. The processing unit can process the data, and sort the data to find the data that the network operations staff typically need to display. Geolocation information may also be derived, to derive the user's location associated with each individual file of data.
However, this known prior art has disadvantages. It is difficult to process the data efficiently, due to the volume of data involved. This approach is also problematic with cellular mobile communications that have to be enlarged. It is in particular expensive to size the data processing unit appropriately, for a network whose future size is unknown. There is no practical way for this type of architecture to grow ‘organically’ as the network expands.
Looking at the processing of data in such a system, several types of information might be of value to the operations staff of the cellular mobile communications network. These include ‘Quality of Service’ (QoS) information and ‘Geolocation’ information:    a) Quality of Service information reveals how well the network is supporting users of the network. A high quality of service may be indicated by a very low rate of ‘dropped’ calls, or by very few mobiles experiencing low or highly variable signal strength. In most known cellular networks, quality of service information is reported on a ‘per-cell’ or ‘per-sector basis’. This means that the network statistics obtained will only provide an indication of, for example, the average data rate or the average number of dropped calls in a given sector.    b) Geo-location is the identification of the real-world geographical location of a mobile communication unit. Geo-location of mobile communication units can be performed in several ways. These include providing a mobile communication unit with positioning equipment, such as GPS, or using network and mobile measurement data from nearby cells.
The network statistics referred to above, which only provide the average data rate or the average number of dropped calls in a given sector, are insufficient for some tasks faced by network operators. Some network operators have therefore tried to improve the information available on service levels and/or available for deriving geolocation information.
One attempt to do this has involved compiling more comprehensive data, for a limited time, on what exactly is happening in one sector or one cell of a network. The operator initially makes a decision which cell to monitor, and for how long. The cell may be chosen, for example, because it is the cell in which a user who has made a complaint lives. The duration of the monitoring may depend on the amount of storage that the operator considers justified for the investigation. There are two reasons why this is only done rarely, as follows:    (i) A vast amount of data is created, even for a short time period such as a few hours. Storing this data in a retrievable form is very expensive.    (ii) If data concerning calls made in a sector or cell of a network is captured for a period of a few hours, it then requires specialist post-processing. Any information that can be derived from the data about a user or part of the network is then often only available several hours after the end of the data capture. This may be several days after a user has made a complaint. Such information is often only of limited value.
Prior art approaches (i) and (ii) above amount to a ‘batch processing’ technique. This approach gathers all of the information for a time period after a problem arose in a network sector. The data is essentially obtained manually, by the operator of the network. After capture of the data, it is then ‘fed’ to the processing system, which will then process the information off-line. This typically results in a delay of many hours, between the event of interest taking place and the resulting diagnostic information being available.
The fact that the process is ‘retroactive’ may also be a problem. The approach will only assist in identifying a fault:    (i) If it is a network fault that is still detectable, rather than one that only occurs intermittently. An intermittent fault could have many causes, such as one that occurs at particular times of day, or under certain external circumstances such as ambient temperature or vibrations of an antenna due to a particular wind direction.    (ii) If the user happens to be active during the few hours when the data is captured, for faults that are entirely due to the user's handset.
FIG. 1 provides a more detailed view of one prior art approach. The system of FIG. 1 seeks to extract data concerning activity in one part of a cellular mobile communications system, for a period of a few hours. The data may be obtained from a radio network controller (RNC) 112 or similar network element. Server 120 may then process this data. The processing may be specifically to find data about a particular user, who has reported a fault. More general information may be obtained, for example, the quality of service information for a group of users.
The amounts of data obtained even by the system of FIG. 1 are extremely large. The data may be sent to a database server 130 and on to a storage system 140. All prior art systems known to the inventors that attempt to record all data about what is happening in a sector or cell, place this data, in its entirety, either:    (i) On a single storage device, such as storage system 140 shown in FIG. 1; or    (ii) On a series of linked storage devices, connected to a database server such as server 130 shown on FIG. 1.
However, the prior art system may even aim to store all data for a series of RNCs 112, 114, 116. This volume of data would typically require several storage devices, each linked to database server 130.
A user of the system of FIG. 1 may seek to examine some part of the large volume of data on storage system 140. The user is shown as reference 150. User 150 may access the storage system 140 via an application server 160. The system of FIG. 1 may also include information about the configuration of the network containing RNCs 112, 114 and 116. This information may have been obtained from outside the system shown on FIG. 1.
The user faces several problems, such as the data being available on storage system 140 many hours after a fault may have occurred, and the difficulty in finding individual pieces of information.
It might be assumed that it is possible to sort the acquired data and ‘throw away’ the information which is not required for display and reporting purposes. However, this has proved unacceptable in prior art systems, because the personnel in the network operations centre have a requirement to be able to diagnose problems with particular calls, or particular user devices. It may also be necessary to diagnose a systemic fault with a particular brand or model of phone, or other user terminal device.
If we assume that an attempt is made using the system of FIG. 1 to store all data, from all RNCs 112, 114 and 116 of a mobile communications system, then the storage and retrieval system shown in FIG. 1 has very significant disadvantages. When seeking information about, for example, an individual handset or user, the whole of the data in storage device 140 must be searched and processed. This is necessary, in order just to extract the relatively small amounts of data which the network operations centre in a radio network needs, for example, to make day-to-day judgements upon the quality of service offered by the network, to its users.
The ‘raw’ information which must be searched amounts to some ten times the amount of data which is typically required for display to the network operations managers. The processing of this unnecessarily large amount of data makes the reporting process very slow. In a typical prior art approach, the reporting process can take many hours. As a consequence, the information is therefore available to the network management centre some significant time after the user's phone-calls or data sessions to which that quality-of-service data refers.
Prior art systems have typically involved solutions that involve very large data stores, which are expensive. These systems often only provide useful information many hours after events in a network have occurred.